This invention relates to the transport of materials, and, more particularly, to the automatic transport of sheet materials.
It is often necessary to move materials from one position to another. For example, corrugated or cardboard sheets, often in stacks, are moved from a receiving position and loaded into a hopper and fed to a press where they are imprinted with a desired legend.
Although the stacks can be transported manually from their receiving position and manually loaded into the hopper, it is desirable to automate the loading For that purpose a number of arrangements have been proposed. Representative examples are U.S. Pat. No. 3,422,969 which issued to J. A. Miller et al. in January 1969; U.S. Pat. No. 3,643,939 which issued to H. A. Nussbaum, et al. in February 1972; and U.S. Pat. No. 4,119,219 which issued to Carl R. Marschke on Oct. 10, 1978.
Other arrangements are disclosed in Welk U.S. Pat. No. 2,318,132 which issued May 1943; Krinke U.S. Pat. No. 3,262,697 which issued July 1966; Parenti, et al. U.S. Pat. No. 3,860,234 which issued January 1975; and Krebs U.S. Pat. No. 3,885,781 which issued May, 1975.
Still other patents relating to the transport of material are Smith U.S. Pat. No. 1,141,277 which issued June 1915; Palmer U.S. Pat. No. 2,553,719 which issued May 1951; Lundall U.S. Pat. No. 2,778,477 which issued January 1957; Parker U.S. Pat. No. 2,829,759 which issued April 1958; Martin U.S. Pat. No. 2,901,250 which issued August 1959; Gerrans U.S. Pat. No. 2,966,253 which issued December 1960; Letchworth U.S. Pat. No. 3,297,174 which issued January 1967; Thull U.S. Pat. No. 3,464,537 which Issued September 1969; Marschke et al. U.S. Pat. No. 3,724,687 which issued April 1973; Hoke et al., U.S. Pat. No. 4,079,644 which issued Mar. 21, 1978; Marschke U.S. Pat. No. 4,200,276 which issued Apr. 29, 1980, Marschke U.S. Pat. No. 4,235,432 which issued Nov. 25, 1980; and Rodewald U.S. Pat. No. 4,273,325 which issued June 16, 1981.
The foregoing and other prior art transport systems have a number of disadvantages. In general they are characterised by significant complexity and insufficient reliability. In addition, if there is a mechanical or other failure which requires a temporary shutdown for repair, the interposition of the transport system between a receiving or input station and an output location interferes with the continued use of the output equipment.
In the case of U.S. Pat. No. 3,422,963, a stack that is to be transported to an output location is upset on an incline where the weight of the sheets against one another can interfere with the desired output feed. In addition, the upset is achieved by the tilting of slats which form a backrest and which have to be lowered sufficiently to reduce the weight of the upper sheets of the stack against the lower sheets. As a result, there is an inadequate gravitational effect for the proper feed of the upper sheets along the slats. The system further employs an output conveyor which has a greater angle of inclination than the inclined conveyor that feeds sheets to it. This change in angle of inclination produces a further impediment to the proper feed of sheets. The impact of oncoming sheets can produce so much pressure against the sheets on the incline that jamming can result,
In U.S. Pat. No. 3,643,939 it is necessary to employ a transfer conveyor that requires rotation with a full load through an angle greater than 90 degrees. The result is a system of significant electrical and mechanical complexity.
In U.S. Pat. No. 4,119,219, the edges of the upper portion of a stack of sheets are driven into a rotating roll which raises the edges in succession and then forms a lip with a second roll for the feed of a batch of sheets. If the edges are not raised in succession, or if the two rolls are not moved properly, jamming can result.
Transport systems which do not prevent through-flow of materials when there is a temporary shutdown are disclosed in Pulda U.S. Pat. Nos. 3,982,750 which issued Sept. 28, 1976 and 4,008,890 which issued Feb. 22, 1977. They, however, have a substantial spacial requirement.
Accordingly, it is an object of the invention to facilitate the automatic transport of materials from an input position to an output position. A related object is to facilitate the transport of sheet materials.
Another object of the invention is to provide a comparatively compact transport system which will not prevent the through-flow of materials when the system is temporarily shut down, for example, for repair.
Still another object of the invention is to speed the transport of materials. A related object is to eliminate the need for shingling in the transport of sheet materials. Another related object is to achieve batch feeding of materials with reduced chance of jamming.
Yet another object of the invention is to facilitate the upset of stacks of large and heavy sheets of material. A related object is to permit the selective reorientation of batches of material.
A still further object of the invention is to control the throughput of a transport system to insure a continuous and adequate supply of material at the system output.